Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered; the description goes further by disclosing the pagination contract (has_next_page + next_cursor, pass next_cursor as cursor) and the credit cost model with a minimum and bulk waiver. The cost phrasing ('tiered by page fill') is somewhat cryptic, keeping it just short of a 5.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short, front-loaded lines: purpose first, then pagination mechanics, then cost. No filler sentences and every line carries operational information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description usefully names the return fields (has_next_page, next_cursor), and annotations cover the read-only profile. The remaining gap is the unaddressed ambiguity with user_followers/list_followers and the undocumented pageSize, which an agent may need to call correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description carries the burden; it explains cursor use well, and userName is self-evident, but pageSize (default, maximum, valid range) is undocumented in both schema and description, leaving one of three parameters opaque.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Page through the accounts a user follows, newest first'), which an agent can distinguish from a bare 'list users'. It does not, however, name or contrast with the confusingly similar sibling user_followers (accounts following the user) or list_followers, leaving differentiation to inference.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied by the purpose statement and the paging contract, but there is no explicit when-to-use / when-not-to-use guidance and no routing to alternatives such as user_followers, user_followers_ids, or user_verified_followers. Adequate but leaves the agent to figure out which following/follower tool applies.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.